21r0 MINIiRALOGICAL NOTIiS to have Iengthenedbecause the ratio of Mg2+:Al3+in the starting ma- terials was greaterthan the ratio of 7 :3" Brucite was presentin Run V-9 and boehmite was present in Run \,'-10; from this it seemsthat the range of the solid solution of Mgz+ and Al3+ in the hydroxide layer is limited. Valleriite was not produced at the temperatureof 700"C in any of the runs, and valleriite was also not produced at the temperature of 650'C in Run V-3. From this fact, the upper stable temperature of this minerai appearsto be between600oC and 650oC.

Rolnnrxcrs

Evexs, H. T., Mrr,rox, C., Cn.ro, E. C. T., Arr-rr, L, Mnln, C., INcnau, B., eNl Brnmn, R. A. (1964) Valleriite and the neu' iron sulfide, mackinawite, U. S. Geol,.Stut. Pro.f. Pap. 475'D, 64-69. -, AND Ar.r-umw, R (1968) The cr5'5111structure and cr1'stal chemistry of valleriite, Z. Kristallo gr., 127, 73-93. Senrmcnt, G. (1968) Electronprobe analyses of mackinarvite and valleriite, Neues Jahrb. M iner al. M onatsh. 8, 252-258. 'fut:rr,n, 9. p. (1949) Two pressure vesselsfor silicate-rvater systems, Geol. Soc.Amer. Buli. 60. 1727,1729

TIIE AMERICAN I{INERALOGIST, \IOL 55, NOVEMBDR-DECEMBER, 1970

A "VALLERIITE-TYI)E" X{INERAL FRO\{ NORIL'SK, WESTERN SIBERIAI

D. C. Hanus, L. J. Cenu, J. M. Srowanr, Mineral' Sciences Diaision, Mines Branch, Ottazua.

Alstnecr

Electron microprobe analysis of a "valleriite-type" mineral from Noril'sk, western Siberia, yields a formula (CuoggsFerooaSz).1.472 [Fe(OH)z], u'hich is the most iron-rich variant of this mineral reported to date.

INrnotucrtox The structure of valleriite from Loolekop, South Africa, determined very recently by Evans and AIImann (1968), has been interpreted as Iayers of copper-iron sulphide alternating with layers of Mg-AI hydrox- ide. The formula for the Loolekop material is

(Fe1.q7Cu6.e3Sr) '1.526[MBo.e sAlo rr(OH) r]. Springer (1968) re-examined valleriites from two localities: Kaveltorp, Swedenand Palabora, South Africa with the electron microprobe an-

l Sulphide Research Contribution No. 20, Mineral SciencesDivision. M TN ].R-4LOGI C A L,!\ OT] iS

Frc. 1. Photomicrograph showing the oriented "valleriite" inclusions (5) in a lath (3), set in a matrix of talnakhite (1). The surface of the "valleriite" varies from smooth to rough. alyzer.This work showedthat the Palaboramaterial is the ordinary Mg- and Al-containing valleriite, whereas the Kaveltorp samples contain more iron than can be accountedfor by the sulphide sublattice. This suggeststhat there must be someiron in the hydroxide lattice replacing aluminum or magnesium.The formula derived for the Kaveltorp miner- al is

(Cus.s1Fe1.1eSz). 1.56[M96 33Fe6 s7(OH)2]. In addition to the ordinary valleriite at Palabora,there is alsoanother variety of this mineral, which occurs in the -apatite-olivine rock of that district. This valleriite contains more iron and lessaluminum than the ordinary valleriite, and gives a formula

(Cu1.saFes.e6Sr)'1.67 [M go.zbAIo.osFeo.ro(OH)z]. Valleriite from Noril'sk, western Siberia, has been reported inde- pendently by Genkin and Vyal'sov (1967), Cabri and Traill (1966), and Cabri (1967). Genkin and Vyal'sov reported on valleriite and mack- inawite, and gave X-ray powder data and optical and heating properties for valleriite, including X-ray powder data for the Noril'sk "valleriite." 2ll) I'IINI:.1

Talr-n 1. X-R.q,v Powoen Dmln,rcrrolc D,rra lon "VAr-LBRrrrE-TvpE" Mrrtrnar. lrou Nonrr,'sr, WBsrrnw Srlpnre

This St LdVyal'sov (1967) a:3.778+ Noril'sk c:34.747+ .O1 (2) (3)

d(calc)A d(meas;A 1(est) d(meas)A 1(est) d(meas)A

t1 nt 11382 9 11.38 3 + I I .JO 2 7.24" 00.6 .5.691 l0 .5.69 10 5.65 l0 5.71 00.9 3.794 8 3 .788 5 J.lt 5 3.81 10.1 3.257 9 3.259 o 3.28 9 3.27 lnt 3.214 4 324 i 321 2 3.1+6" 10.4 3 055 o 3 .049b 4 3 .03 10.5 2.951 I 2 952 00.12 2.846 2 2.845 1 2.85 2.79 z 2.770" 1 2.77 l0.7 2.7li- 2 2 674" 10.8 2.597 1 2.592 4 2 486" 3 248 J 2.51 10.10 2.363 1 2.359 3 2.36 00.15 ' JJJ) 2.269 3 227 3 228 10 TI 2.252( o J 2.142" 5 2.14 10.13 2.048 J 2.049 10.14 1.956 1 1 958 00.18 1.8e71 1.897 6 1.902 7 1 911 11.0 1.889i 7 11.3 1.864 7 9 t .864 2 r.877 11.6 1.793\ 10 16 1.788 I 10.T7 1.712.i 11.9 r.692f 1.692 20.1 1.6341 20.2 1.6291 1 630 t OJJ 1.633 00.27 1.626) 20.4 1.609r, 205 1

114.6 mm dia. Debve-Scherrer Camera. Fe-l'iltered Co Tladiation Spacegroup R3rir (Evans a;d Allmann, 1968). 'Extra reflections. r, Talnakhite reflections. (2) Vein formation in "cubic ". (3) ltine-grained lamellar crvstals of valleriite from a cavity in "cubic chalcopyrite".

Cabri's identification was based on an X-ray powder pattern using a .i7.3-mm-diameter Debve-Scherrercamera, and the similarity of its optical propertiesto those of other valleriites.He was not certain of the identitv of similar finer grained rnaterial which occurs as replacements MINER-ALOGICAL NOTES 2rt3 within cubanite lamellaeand reported this also as valleriite or mackina- wite; hence,a restudy of this material was undertaken. For a description of the copper-nickelores of the Talnakh deposit, Noril'sk, the readeris referredto a recent paper by Genkin el al. (1969).

Ttto t'VelrBRrrrE-TYPE" MtNBner Electron microprobe analyseswere macieof the Noril'sk "valleriite" in a vuggl- sample kindly supplied by the Leningrad Mining Museum and labelledas "cubic chalcopyrite." Analysesof inclusionsin cubanite (Figure 1) and of larger areasof "valleriite" that had previously been X rayed, gave an averagecomposition f or several grains of Fe 43.8* 0.5percent, Cu 20.0t0.5 percent,S 20.3+0.5percent, total 84.1*4 per- cent. No other elementsdown to, and including, sodium could be de- tected;magnesium and aluminum, in particular, werelooked for, but not detected. The X-ray powder diffraction data (Table 1) of the Noril'sk material, which contained a minor amount of talnakhite (name used for the new copper-ironsulfi.de described by Cabri, 1967),can be indexedas valleriite, using the structure of Evans and Allmann (1968), except for a few re- flections. Some of these extraneousreflections were also reported b1' Genkin and VyaI'sov for the Noril'sk "valleriite." Sinceimpurities other than talnakhite were not detected with the microprobe, the extra re- flectionsmust be attributed to the structure of the mineral. Although the optical propertiesof the Noril'sk mineral are somewhal similar to other valleriites, the differencesare distinct enough to be a guide to its identification. Chamberlain and Delabio (1965), reported the optical propertiesof valleriite as dull bronze,similar to graphite in color, with extremebireflectance from cleamv bronze to purple at high magnifi.cation.Anisotropism was extreme,with colorsvarying from white to bronze.The Noril'sk material, however,is bluish gray, with a distinct bluish color in contrast to magnetite.Bireflectance is moderate,varying from a light grey to a dark bluish gral', in comparisonto the bronzecolor of valleriite. Anistropism is distinct, but less intense than that of val- Ieriite, with colorsvarying from light 1'ellowto reddish purple. Drscussrox The electron microprobe analysis of the so calied "valieriite'in the Noril'sk sampleyields a formula

(cu6 ee5Fe1.6o15z). 1.472 [r'e(OH)r]. From the formula, the calculated OH-concentration is 15.8 percent 211+ MINITRALOGICAL NOTES

which, combined with the microprobe analysis, gives a total of 99.9 percent. The X-ray powder pattern, indexed on Evans and Allmann's hexagonal cell vields cell dimensionso 3.778 and.c 34.147.A which are in close agreementwith that of normal valleriite oI a 3.792 and c 34.10 A. The Noril'sk mineral appearsto representthe end member of a seriesof "valleriite-type" minerals with the Mg-Al positions in the hl,droxidelayer occupiedb.v Fe.

Acxxorvr,Blcrnrxr

We r,vish to thank Dr J. Rucklidge, University of Toronto, who suggested the "val- leriite-type" formula from our microprobe analysis

I{rlrnrNcns

Caenr, L. I. 0967) A nerv copper-iron su1fide.Econ. Geol.62,9L0,925 exn R. J. Tnr,rr,r. (1966) New palladium minerals from Noril'sk, Western Siberia. Can. Mineral. 8, 541-550. Cu,trtrrnr..trm, J. A., eno R. N. Dnreero (1965) Mackinalvite and valleriite in the Muskox intrusion. Amer. Mineral 50,682 695. IivaNs, H. T., Jn., ano R. Ar.r.ulNN (1968) The and crystal chemistr.v of valleriite. Z. Kristallogr., 127, 73-93. GnNr

THE AMERICAN MINERALOGIST, VOL .'5, NOVEMBER-DIICEI\{BER, 1970

TUNGSTENIANWULTENITES, MINA SAN SAMUEL, CACHIYUYODE LLAMPOS,CHILE AraN H. CrAnr, Department oJ Geologi,calSciences, Queen's Linirer sity, K in gston,Ontario, Can ada

AND Rrcnenl H. Srr.r.rron,Instituto de Inaestigaciones Geollgi,cas,Casil,la 10465,Sontiago de Chile.

ABSTRACT

Chemical analyses and cell dimensions are presented for a wulfenite and for two Pb(Mo,W)Or solid solutions from northern Chile. The latter are more molybdenum-rich than previously described "chillagites", and indicate that a complete series from wulfenite to stolzite may be represented in nature.